scispace - formally typeset
Search or ask a question

Showing papers by "Mobil published in 1972"


Journal Article•DOI•
TL;DR: A refined scheme of reefal limestone classification, which places more emphasis on the > 2 mm components (conglomeratic fraction) and on the mode of organic binding, allows for a more detailed facies description of organic buildups as mentioned in this paper.
Abstract: A refined scheme of reefal limestone classification, which places more emphasis on the > 2 mm components (conglomeratic fraction) and on the mode of organic binding, allows for a more detailed facies description of organic buildups. The classification has been applied to Late Devonian organic buildups which outcrop on northeastern Banks Island, Canadian Arctic Archipelago. The distribution and sequences of facies in one organic buildup has led to the determination of absolute water depth limits of three major Late Devonian paleoecological zones. Corals were the dominant fauna below 70 feet (21 m.); tabular stromatoporoids flourished between 70 feet (21 m.) and 30 feet (9 m.) of water depth; massive stromatoporoids were the dominant fauna between 30 feet (9 m.) and sea level. The main controlling factor on the depth limits of the zones was wave energy (normal wave base, 30 feet [9 m.]; storm wave base, 70 feet [21 m.]).

304 citations


Patent•
Donald A Haase1, Robert E Reed1•
21 Sep 1972
TL;DR: In this article, a method for the production of embossed laminar thermoplastic film structures is described, which consists of supplying a first length of a thermoplastic film onto the surface of a patterned roller, and subsequently heating the patterned surface to raise the temperature of the film in those areas which are in contact with the infrared absorbent pattern.
Abstract: A method for the production of embossed laminar thermoplastic film structures comprising supplying a first length of a thermoplastic film onto the surface of a patterned roller, portions of which pattern are capable of absorbing infrared radiation, subsequently heating the patterned surface to raise the temperature of the film in those areas which are in contact with the infrared absorbent pattern, and finally superimposing a preheated film onto the film on the surface of the patterned roller to produce a laminar structure bonded together along a plurality of intersecting heat seal lines.

120 citations


Patent•
L Strange1•
13 Nov 1972
TL;DR: In this article, a method of producing hydrocarbons from a hydrocarbon-bearing formation penetrated by a pattern of wells including at least one injection well and two production wells spaced relatively close one to the other.
Abstract: This specification discloses a method of producing hydrocarbons from a hydrocarbon-bearing formation penetrated by a pattern of wells including at least one injection well and two production wells spaced relatively close one to the other. The production wells are stimulated by heating the formation to form a heated zone about the production wells, for example, by injecting steam via the wells into the formation. A forward drive in situ combustion process is initiated at an injection well and production of hydrocarbons is initiated from the reservoir from at least one of the production wells. The heated zone is maintained by injecting heat, for example, steam, via another of the production wells while continuously producing hydrocarbons from at least one production well from within the heated zone. The producing wells are alternately employed for producing hydrocarbons from the formation and for injecting heat into the formation to maintain the heated zone about the producing wells.

119 citations


Patent•
12 May 1972
TL;DR: In this article, a process for the kylocalylation of aromatic hydraconauts is described, in the presence of a catalyst coming into contact with a cylstalline aluminosilicon aluminometer.
Abstract: A PROCESS IS PROVIDED FOR ALKYLATION OF AROMATIC HYDROCARBONS BY CONTACTING SAME WITH AN ALKYLATING AGENT IN A REACTION ZONE MAINTAINED UNDER CONDITIONS SUCH THAT SAID ALKYLATION IS ACCOMPLISHED IN THE VAPOR-PHASE AND IN THE PRESENCE OF A CATALYST COMPRISING A CRYSTALLINE ALUMINOSILICATE ZEOLITE CHARACTERIZED BY A UNIQUE X-RAY DIFFRACTION PATTERN, SAID CATALYST UNDER SAID CONDITIONS BEING CAPABLE OF AFFORDING A HIGH AND SELECTIVE YIELD OF DESIRED ALKYLAROMATIC PRODUCT. SAID ALKYLATION PROCESS IS ACCOMPANIED BY A SYSTEM FOR TRANSALKYLATION OF THE POLYALKYLAROMATIC PORTION OF THE EFFLUENT FROM SAID ALKYLATION PROCESS. THERE IS ALSO PROVIDED, WHEN SAID REACTION ZONE IS COMPRISED OF A SERIES OF REACTOR STAGES, A QUENCH FOR EFFLUENT FROM SAID STAGES BETWEEN SAID STAGES. ALSO, A CATALYST STEAM REGENERATION METHOD IS PROVIDED.

113 citations


Journal Article•DOI•
TL;DR: In this article, the authors measured the varve couplets in the Castile and Salado formations in the Delaware Basin and found that they are synchronous, and each couplet is interpreted as representing an annual layer of sedimentation.
Abstract: Laminations in the Upper Permian evaporite sequence in the Delaware Basin appear in the preevaporite phase of the uppermost Bell Canyon Formation as alternations of siltstone and organic layers. The laminations then change character and composition upward to organically laminated claystone, organically laminated calcite, the calcite-laminated anhydrite typical of the Castile Formation, and finally to the anhydrite-laminated halite of the Castile and Salado. Laminae are correlative for distances up to 113 km (70.2 mi) and probably throughout most of the basin. Each lamina is synchronous, and each couplet of two laminated components is interpreted as representing an annual layer of sedimentation—a varve. The thickness of each couplet in the 260,000-varve sequence (a total thickness of 447.2 m, 1467 ft) has been measured individually and recorded and provides the basis for subdividing and correlating major stratigraphic units within the basin. The uppermost 9.2 m (30.3 ft) of the Bell Canyon Formation contains about 50,850 varve couplets; the Basal Limestone Member of the Castile about 600; the lowermost anhydrite member of the Castile (Anhydrite I) contains 38,397; Halite I, 1,063; Anhydrite II, 14,414; Halite II, 1,758; Anhydrite III, 46,592; Halite III, 17,879; and Anhydrite IV, 54,187. The part of the Salado collected (126.6 m) contains 35,422 varve couplets. The Bell Canyon-Castile sequence in the cores studied is apparently continuous, with no recognizable unconformities. The dominant petrologic oscillation in the Castile and Salado, other than the laminations, is a change from thinner undisturbed anhydrite laminae to thicker anhydrite laminae that generally show a secondary or penecontem-poraneous nodular character, with about 1,000 to 3,000 units between major oscillations or nodular beds. These nodular zones are correlative throughout the area of study and underly halite when it is present. The halite layers alternate with anhydrite laminae, are generally recrystallized, and have an average thickness of about 3 cm. The halite beds were once west of their present occurrence in the basin but were dissolved, leaving beds of anhydrite breccia. The onset and cessation of halite deposition in the basin was nearly synchronous. The Anhydrite I and II Members thicken gradually across the basin from west to east, whereas the Halite I, II, and III Members are thickest in the eastern and northeastern part of the basin and thicken from southeast to northwest. This distribution and the synchroneity indicate a departure from the classical model of evaporite zonation.

111 citations


Patent•
Demmel Edward J1, Owen Hartley1•
19 Dec 1972
TL;DR: A combination operation utilizing a mixture of small and large pore crystalline aluminosilicates having activity and selectivity for cracking hydrocarbons and cyclization of gaseous products of cracking in a dual conversion zone operation is described in this paper.
Abstract: A combination operation utilizing a mixture of small and large pore crystalline aluminosilicates having activity and selectivity for cracking hydrocarbons and cyclization of gaseous products of cracking in a dual conversion zone operation is described. The catalyst components used contribute to the function of each other to produce material of relatively high octane rating and the small pore crystalline material is a ZSM-5 type of catalyst.

90 citations


Patent•
Cattanach J1•
17 May 1972
TL;DR: In this article, a process for the preparation of AROMATIC COMPOUNDS in high-yield environments is described, which involves contacting a PARTICULAR FEED CONSISTING ESSENTIALLY OF MIXTURES OF PARAFFINS, AND/OR OLEFINS, and/or NAPTHENES with a CRYSTALLINE ALUMINILICATE OF the ZSM-5 type under conditions of TEMPERATURE and Space VELOCITY.
Abstract: A PROCESS FOR THE PREPARATION OF AROMATIC COMPOUNDS IN HIGH YIELDS IS SET FORTH WHICH INVOLVES CONTACTING A PARTICULAR FEED CONSISTING ESSENTIALLY OF MIXTURES OF PARAFFINS, AND/OR OLEFINS, AND/OR NAPTHENES WITH A CRYSTALLINE ALUMINSILICATE OF THE ZSM-5 TYPE UNDER CONDITIONS OF TEMPERATURE AND SPACE VELOCITY SUCH THAT A SIGNIFICANT PORTION OF THE FEED IS CONVERTED DIRECTLY INTO AROMATIC COMPOUNDS.

89 citations


Patent•
H Owen1•
19 Dec 1972
TL;DR: In this article, a multistage hydrocarbon conversion operation in the presence of a dual cracking catalyst composition comprising ZSM-5 type material is described for the production of gasoline and olefinic components.
Abstract: A multistage hydrocarbon conversion operation in the presence of a dual cracking catalyst composition comprising ZSM-5 type material is described for the production of gasoline and olefinic components. In a particular aspect an integrated refinery operation for producing gasoline by converting straight run hydrocarbons and recycle products of cracking in the presence of the dual cracking component catalyst is discussed with a view to identifying the operating methods relied upon for enhancing the operation.

81 citations


Patent•
F Bustin1•
23 Aug 1972
TL;DR: In this paper, a thin polyethylene film, of 0.025 mm, or less thickness, is passed between a pair of matching embossing rollers having, respectively, negative and positive embozing patterns on their surface, driven at the same circumferential speed, the speed of the embelling rollers being suitably chosen to allow the film to pass between the rollers while being embossed.
Abstract: Thin polyethylene film, of 0.025 mm, or less thickness is passed between a pair of matching embossing rollers having, respectively, negative and positive embossing patterns on their surface, driven at the same circumferential speed, the speed of the embossing rollers being suitably chosen to allow the film to pass between the rollers while being embossed. The rollers are preferably cooled; the continuous embossed web, if 2-layer and tubular, is then inflated to separate the two-embossed layers, which can then be heat-sealed together at intervals and the edge slit to form separable bags, when rolled up in a single roll for ease of dispensing; the embossing patterns preferably, but not necessarily match at least at the heat-seal lines.

69 citations


Patent•
P Chu1•
07 Jan 1972
TL;DR: In this article, a method of removing the organics from an ORGANIC CATION-CONTAINing ZEOLITE is proposed, which is capable of at least 0.25 VOLT.
Abstract: A METHOD OF REMOVING THE ORGANIC CATION FROM AN ORGANIC CATION-CONTAINING ZEOLITE WHICH COMPRISES CONTACTING THE SAID ZEOLIT WITH A SOLUTION OF A COMPOUND WHICH HAS A STANDARD OXIDATION POTENTIAL OF AT LEAST 0.25 VOLT.

66 citations


Patent•
Demmel Edward Joseph1, Hartley Owen1•
19 Dec 1972
TL;DR: In this paper, a method and system for cracking hydrocarbons and regeneration of the catalyst is described with particular emphasis directed to partially restoring the activity of the catalysts after an initial hydrocarbon conversion use by heat soaking the catalyst at an elevated temperature before use in a second hydrocar conversion zone.
Abstract: A method and system for cracking hydrocarbons and regeneration of the catalyst is described with particular emphasis directed to partially restoring the activity of the catalyst after an initial hydrocarbon conversion use by heat soaking the catalyst at an elevated temperature before use in a second hydrocarbon conversion zone. This case is a division of application Ser. No. 595,833, filed Jul. 14, 1975.

Patent•
30 Jun 1972
TL;DR: A logging-while-drilling tool is a tool that is adapted to be positioned within the drill string of a well drilling apparatus as discussed by the authors, which has a turbinelike, signal-generating valve which opens and closes at a defined rate to generate a pressure wave signal in the drilling fluid which is representative of a measured downhole condition.
Abstract: A logging-while-drilling tool which is adapted to be positioned within the drill string of a well drilling apparatus. The tool has a turbinelike, signal-generating valve which opens and closes at a defined rate to generate a pressure wave signal in the drilling fluid which is representative of a measured downhole condition. The tool includes spring means to normally bias the rotor away from the stator of the valve. The force constant of the spring means is greater than the pressure drop across the rotor at low flow rates but is less than the pressure drop at the flow rate at which the tool begins operation. This allows the tool to maintain a large gap between the rotor and stator prior to operation of the tool or during periods of nonoperation thereby alleviating the problem of plugging and/or jamming of the valve. During normal operation the net force holding the rotor down, i.e., the force due to hydraulic pressure drop minus the spring force, is relatively small so that the rotor will ride up over and free itself from material which may become lodged in the gap, thus alleviating jamming of the valve. Also, structural features of the rotor aid in alleviating plugging of the valve.


Patent•
Messenger J1•
01 May 1972
TL;DR: In this article, a specification for a lightweight hydraulic cement is given for the use of lightweight slurries formed by combining this lightweight cement with water, and to lightweight concrete formed by the setting of the slurries.
Abstract: This specification is directed to a lightweight hydraulic cement, to the use of lightweight slurries formed by combining this lightweight cement with water, and to lightweight concrete formed by the setting of the slurries. The lightweight hydraulic cement is comprised of hydraulic cement, anhydrous sodium metasilicate, and hollow sealed spheres; a lightweight slurry is formed by mixing the lightweight cement with water and the slurry is used for treating wells that penetrate the earth. This lightweight slurry may also be used for forming lightweight concrete which in turn is useful for such things as building material.

Journal Article•DOI•
TL;DR: In this article, the metal particle size diameters and particle size distributions of platinum supported on alumina catalysts have been investigated using small angle X-ray scattering techniques and the primary parameters derived from the scattering of X-rays by the platinum crystallites are RG, the Guinier radius, and RP, the Porod radius.

Journal Article•DOI•
L.D. Rollmann1•
TL;DR: In this article, the infrared spectra of the resultant polymer complexes with those of the monomeric analogs were compared by comparing the infrared spectrum of the resulting polymer complexes to those of monomers.

Patent•
A Schwartz1, Veigh H Mc1•
19 Dec 1972
TL;DR: In this article, a method and system for converting hydrocarbons with a dual cracking component comprising ZSM-5 is described, where the products of a large pore size cracking catalyst are passed into a dense fluid bed of catalyst comprising Z SM-5 catalyst for the production of aromatics and/or olefins suitable for alkylation with a paraffin.
Abstract: A method and system for converting hydrocarbons with a dual cracking component catalyst comprising ZSM-5 is described wherein the products of a large pore size cracking catalyst are passed into a dense fluid bed of catalyst comprising ZSM-5 catalyst for the production of aromatics and/or olefins suitable for alkylation with a paraffin.

Patent•
Paul T. Allen1, B M Drinkard1•
28 Apr 1972
TL;DR: An improved method for separation and isolation of individual components contained in a C8 aromatic mixture such as p-xylene and ethylbenzene, by contacting the mixture with an aluminosilicate zeolite which has been contacted with an organic-radical substituted silane, was proposed in this article.
Abstract: An improved method for separation and isolation of individual components contained in a C8 aromatic mixture such as p-xylene and ethylbenzene, by contacting the mixture with an aluminosilicate zeolite which has been contacted with an organic-radical substituted silane to modify the characteristics of the zeolite

Patent•
N Commisso1•
14 Jul 1972
TL;DR: A thin gauge plastic cover having reinforcing ribs in its annular side wall and top, and a recessed knob-like handle at its top is disposed on a plate for serving food, for example, in institutions as discussed by the authors.
Abstract: A thin gauge plastic cover having reinforcing ribs in its annular side wall and top, and a recessed knob-like handle at its top is disposed on a plate for serving food, for example, in institutions. The cover has a lower arcuate rim provided with a plurality of spaced inwardly projecting lugs to lock the cover to the periphery of the plate and to space the remainder of the rim of the cover slightly above the periphery of the plate to allow for venting from the interior of the container. The lugs and reinforcing ribs are arranged to prevent covers from sticking to each other when a plurality of covers are nested together.

Patent•
James L. Hagar1, Harold E. Schwartz1•
01 Jun 1972
TL;DR: In this article, the load conditions on a plurality of pumping wells are made by strain gauges mounted on the pumping wells, and a field-located remote terminal unit is connected to each of the plurality of pumps.
Abstract: Measurements of the load conditions on a plurality of pumping wells are made by strain gauges mounted on the pumping wells. A field-located remote terminal unit is connected to each of the plurality of pumping wells. Upon command from a centrally located computer, the remote terminal unit stores the load condition measurements from a pumping well selected by the computer. At some later time the computer retrieves the load condition measurements stored in the remote terminal unit.

Journal Article•DOI•
Francis Gerard Dwyer1•
01 Jan 1972
TL;DR: In many urban areas, due to their sheer number, the automobiles are major contributors to air pollution as mentioned in this paper, which has led to substantial action by the executive and legislative branches of government on both the state and federal levels.
Abstract: In recent years, concern over our environment has led to substantial action by the executive and legislative branches of government on both the state and federal levels. A major environmental concern is that of air pollution. The sources of air pollution are mainly industrial or stationary sources, which includes a wide variety of manufacturing facilities and power plants, and automobiles. In many urban areas, due to their sheer number, the automobiles are major contributors to air pollution.

Patent•
18 May 1972
TL;DR: In this paper, the authors describe the conversion of hydraconians by using a family of skeletons designed as ZSM-5 and described as MOL RATIOS OF OXIDES.
Abstract: CATALYTIC CONVERSION OF HYDROCARBONS IS CARRIED OUT BY CONTACTING THE SAME WITH A FAMILY OF CRYSTALLINE ZEOLITES DESIGNATED AS ZSM-5 HAVING THE COMPOSITION EXPRESSED AS MOL RATIOS OF OXIDES AS FOLLOWS: 0.9 $ M2/NO:AL2O3:YSIO2:ZH2O WHEREIN M IS AT LEAST ONE CATION HAVING A VALENCE N, Y IS AT LEAST 5 AND Z IS BETWEEN 0-40, SAID ALUMINOSILICATES CHARACTERIZED BY A SPECIFIC X-RAY POWDER DIFFRACTION PATTERN.

Patent•
Willett F Baldwin1, Lynn D. Mullins1•
12 Oct 1972
TL;DR: In this paper, a system for detecting the presence of particulate material, e.g., sand, in a fluid stream flowing through a conduit, is presented, which consists of an acoustical probe which is positioned directly into the flow stream.
Abstract: A system for detecting the presence of particulate material, e.g., sand, in a fluid stream flowing through a conduit, said system comprising an acoustical probe which is positioned directly into the flow stream. The probe has a housing in which a transducer, e.g., piezolectric crystal, is suspended. The housing is filled with oil to acoustically couple the transducer to the housing. Particulate material in the flow stream gives up kinetic energy upon striking the housing of the probe which in turn excites the transducer to generate an output signal having a frequency component which is representative of the particulate material. The system includes circuitry which amplifies and filters the output signal to provide a processed signal corresponding to said frequency component and which includes means for utilizing said processed signal, e.g., an alarm activated when a certain sand content condition in the flow stream is exceeded.

Journal Article•DOI•
A. F. Stancell1, A. T. Spencer1•
TL;DR: In this paper, ultrathin crosslinked coatings, of the order of 0.5 microns thick, were deposited from a plasma onto relatively permeable film substrates.
Abstract: Permselectivity was vastly improved when ultrathin crosslinked coatings, of the order of 0.5 microns thick, were deposited from a plasma onto relatively permeable film substrates. In one example, the hydrogen-to-methane permeability ratio was increased from 0.87 to 33, and the hydrogen permeability was decreased by just 20% when benzonitrile was plasma deposited onto a silicone–carbonate copolymer film. In another example, the hydrogen-to-methane permeability ratio was increased to 297 when cyanogen bromide was plasma deposited onto a poly(phenylene oxide) film. Such coatings, while effective for the hydrogen/methane pair, had little effect on modifying film permselectivity for isobutene/butene-1, a pair nearly identical in molecular size and solubility. It appears therefore that the coatings can very effectively distinguish between molecules differing significantly in size. Also, since the coatings are so thin, the overall permeability of the coating–substrate composite can be high.


Patent•
L Steffens1•
11 Dec 1972
TL;DR: In this article, a vapor pump driven by the shaft of the meter is used to dispense liquid from a container of volatile hydrocarbons to prevent its escape to the atmosphere during dispensing of volatile liquid.
Abstract: Escape of hydrocarbons to the atmosphere during dispensing of volatile hydrocarbon fuels is avoided by pumping vapor from the container to be filled concurrently with introduction to that container of hydrocarbon fuels which contain volatile components. Suitable apparatus for the purpose include a vapor pump driven by the shaft of the meter which operates an indicater of amount of liquid dispensed.

Patent•
Glass John Richard1•
19 Jun 1972
TL;DR: In this article, the use of a multiple capillary viscometer tube is described, whereby capillary tubes of varying sizes are connected one to another in series and into which a sample liquid is drawn by controlled vacuum.
Abstract: An automatic viscometer featuring the use of a multiple capillary viscometer tube whereby capillary tubes of varying sizes are connected one to another in series and into which a sample liquid is drawn by controlled vacuum. In one of the preferred embodiments of the invention the viscometer utilizes a supply turntable and heated sample jackets for preheating liquid samples, a temperature bath to bring the sample being measured to controlled equilibrium, a series of automatic meniscus sensors to detect the flow of oil, and means for automatically computing viscosity from the sensor output. Thermistors are used as meniscus sensors.

Patent•
W Baldwin1•
12 Oct 1972
TL;DR: In this paper, a means for detecting the presence of particulate material, e.g., sand, in a fluid stream flowing through a conduit, is presented, comprising an acoustical probe which is positioned directly into the flow stream.
Abstract: A means for detecting the presence of particulate material, e.g., sand, in a fluid stream flowing through a conduit, said means comprising an acoustical probe which is positioned directly into the flow stream. The probe has a housing in which a transducer, e.g., piezoelectric crystal, is suspended. The housing is filled with oil to acoustically couple the transducer to the housing. Particulate material in the flow stream gives up kinetic energy upon striking the housing of the probe which in turn excites the transducer to generate an output signal having a frequency component which is representative of the particulate material.

Patent•
M Braid1, D Quinty1•
17 Apr 1972
TL;DR: In this paper, an additive additive made by reacting a PHOSPHONATE with OLEAMIDE to a LUBRICANT IMPARTS IMPROVED FRICTIONAL CHARACTERISTICS THERETO was proposed.
Abstract: THE ADDITION OF AN ADDITIVE MADE BY REACTING A PHOSPHONATE WITH OLEAMIDE TO A LUBRICANT IMPARTS IMPROVED FRICTIONAL CHARACTERISTICS THERETO. IN ADDITION, LEVELS OF CORROSION AND CHATTER AND SQUAWKING NOISES RESULTING FROM INTERRUPTED POWER TRANSMISSION ARE ELIMINATED OR REDUCED TO ACCEPTABLE LEVELS.

Journal Article•DOI•
TL;DR: The Parkman Sandstone and the Cody Shale were formed by ocean bottom currents that flowed northeast, perpendicular to the paleoslope, rather than by downslope turbidity currents as discussed by the authors.
Abstract: The Upper Cretaceous Cody Shale and Parkman Sandstone in the southwestern Powder River basin, Wyoming, were deposited during progradation southeastward of a wave-dominated, high-destructive type of delta. The Cretaceous cordillera in eastern Idaho and southwestern Montana was the source of the homogeneous group of litharenite and feldspathic litharenite sandstones. The source rocks were pre-Belt crystalline rocks, the Belt Supergroup of argillite and quartzite, Paleozoic and Mesozoic sedimentary rocks, and Cretaceous volcanic rocks and ash falls. The upper several hundred feet of the 2,500-ft Cody Shale comprise a flyschlike sequence deposited on the upper prodelta slope. The lower 220 ft of the overlying Parkman Sandstone accumulated on the delta platform and along the strandline. Abundant pillow structures occur in sandstone beds deposited at the top of the prodelta slope and on the outer delta platform. Mapping of structural elements in pillow horizons shows that the subaqueous delta surface dipped southeast with southwest-northeast contours. The Cody graded beds were deposited by ocean-bottom currents that flowed northeast, perpendicular to the paleoslope, rather than by downslope turbidity currents. The sandstone beds on the delta platform were deposited by strong waves and subordinate tidal currents, both of which were highly variable in direction. Cross-bedding consistently dips landward and along shore in the strandline sandstones; they were deposited in a complex of beaches, swash bars, spits, and sub-tidal areas swept by alongshore drift. The upper 200 ft of the Parkman Sandstone are delta-plain carbonaceous mudstones, lensing channel sandstones, and a few thin lignite beds. The region was one of low relief and southeast gradient, with floodplains, meandering stream courses, lakes, swamps, and a coastal marsh with tidal creeks. Lowering of the delta surface by compaction of the thick sequence of prodelta mud resulted in local deposition of 12 to 60 ft of marine sandstone at the top of the Parkman Sandstone which represents the destructional phase of the delta. Subsequent transgression of an unnamed marine tongue of the Cody Shale terminated the delta cycle.